If you want the same size, the Canon S95 is comparable, I'm not sure about the Oly XZ-1's size. I have an F10 and an LX-3: the F10 (and F20, F31) are more pocketable than the LX-3 and are less fiddly for inexperienced users, and the high ISO is still very good for a digicam.
So I'd be tempted to keep the F31 until the release of the iPhone 5, which looks like shipping with a Sony 8Mp sensor - more than enough res for family snapshots, and probably a good enough digicam substitute unless you want shallow dof - which the LX-3 and XZ-1 can deliver with their larger sensors and faster lenses.